Generic devices and methods are employed in the brewing of beer to separate solids of hop products when hopping the wort and the beer, which may take place at any stage during beer production. This so-called aroma hopping may take place by way of the hot brewing liquid as so-called boil hopping or also after fermentation in the finished beer as so-called dry hopping.
In beer production, hop is added to the wort during wort production. This is also called boil hopping. In this case, it is one of the tasks of the hop to add a bitter flavor and hop aroma to the beer. Customarily, hop pellets, which contain solids, or hop extract or also natural hop is used for this purpose. In case of hopping in the boiling process, i.e. during the brewhouse process, the hop is usually added during wort boiling. To bring out the hop aroma, the hop may also be added after hot trub separation, i.e. after the whirlpool and prior to the wort cooler. In this way, the volatile hop aromas are prevented from evaporating and dissipating.
Based on changing customer demands, beer with a strongly pronounced hop aroma is increasingly sought in the market. To achieve said aroma, the beers are increasingly also dry-hopped. This means that hop is added to the beer at the cold stages, preferably after fermentation. This is called dry-hopping. Hop pellets or natural hops are most commonly used for this purpose.
The use of solid hop products, in particular hop pellets, for example, is disadvantageous both at the hot stages and at the cold stages in particular because after extraction of the ingredients, large amounts of residue, so-called spent hops or hop trub particles, remain in the wort and in the beer. These solid residues have to be separated again because they are undesired in the subsequent processes and in the finished beer.
At the hot stages, in case of hop addition during wort boiling, said separation subsequently takes place in the whirlpool, in the wort receiver or by means of a centrifuge, where the hop trub particles are separated together with the protein residue, namely the hot trub.
In order to achieve proper separation, the whirlpool has to have a sufficiently large separating area so as to be able to receive and separate the hop trub. In case of beers with large amounts of hop, the whirlpool vessels will have to be dimensioned correspondingly larger, which leads to additional investment costs as well as to higher losses of wort.
During hopping, the hop trub is separated by filtration or separation, which, however, causes additional costs because the additional trub particles tend to considerably reduce the capacity and performance of the filter and because it becomes necessary to invest in a (potentially custom-built) centrifuge. Also, part of the hop trub particles may lie in the tank in a very compact manner, making them difficult to remove.
From DE 10 2013 101 435 A1, a device and a method for extracting aroma substances from vegetable aroma carriers into a brewing liquid are known. Either a hydrocyclone or a filter, in particular a slotted filter, is used as a solids separating device for separating the insoluble hop trub particles. The use of a hydrocyclone has the disadvantage that adjustment of the capacity of said hydrocyclone to the respectively necessary capacity for hop trub separation is very intricate. Since the hydrocyclone is based on complex flow-mechanical operating principles, the dimensions of the hydrocyclone cannot be easily adjusted depending on the respectively necessary capacity for hop trub separation. The use of a filter for hop trub separation has the disadvantage that these filters, in particular sieve filters, are easily clogged and will have to be laboriously cleaned for continued use.